Valvular stenosis, also called heart valve disease or narrowed valve, occurs when tissues forming a cardiac valve leaflets become stiffer thereby narrowing the valve opening and reducing the amount of blood that can flow through it.
Valvular stenosis may occur in any of the four valves of the heart: the aortic valve, the mitral valve, the tricuspid valve or the pulmonic valve.
One of the known causes of valvular stenosis is a fibro-calcific degeneration of the valve leaflets wherein one or more of the valve leaflets become calcified and thus thickened and hardened, resulting in a narrowed valve opening.
Current treatments for valvular stenosis primarily involve an open or percutaneous surgery to replace the heart valve with a mechanical or tissue-based replacement heart valve.
Open surgery is done through a median sternotomy and involves a cardiopulmonary bypass of the patient. It is thus a major operation that conveys significant risk of death or serious complications. Moreover, a large class of older patients, as well as those who are frail and/or have multiple comorbidities, face significantly higher surgical risks and are thus excluded from the scope of application of this method.
Novel catheter-based approaches have been developed, such as percutaneous aortic valve replacement, which eliminate the need for open heart surgery. However, these catheter-based approaches are only applicable to selected groups of patients and still involve significant risk of death or serious complications.
Indeed it is estimated that more than 30% of the patients with severe valvular stenosis are excluded from the field of application of both open and percutaneous surgical methods.
Even when a patient fulfils the conditions to receive a replacement valve by open or percutaneous surgery, both mechanical and tissue-based replacement heart valves present significant drawbacks.
Mechanical valves are made from pyrolytic carbon and require a life-time treatment of warfarin anticoagulant, with an accompanying risk of bleeding. While such bleeding events are rare, they are often fatal.
Tissue valves (or “bioprostheses”) come with no requirement for anticoagulation therapy, which reduces the incidence of bleeding. However, the lifetime of a tissue valve is typically 10 to 15 years, often less in younger patients. Over this time the valve will likely be degenerating to the point of requiring replacement, which again carries a significant risk of death. Moreover, tissue valves are also subject to valvular diseases; in particular, they may also develop fibro-calcific degeneration requiring an early replacement.
There is thus a need for a treatment or prevention of valvular stenosis that would involve a less invasive medical intervention with reduced risks, and for a treatment of valvular stenosis that would present benefits in term of long-term recovery of the patient.
The instant invention has notably for object to improve this situation.